Double up on the keying of the words "internal gears." Interested keeps drifting back and forth between describing the problems (with which he has NO experience) of the Nexus 8 and the problems that he (almost) alone in his country seems to have with the concept of "inefficiency" of internal gears. The significance of this so-called "inefficiency" or extra few grams/ounces of weight appears only to matter to someone obsessed with cycling theory or in a constant racing competition mode, rather than practical day to day cycling in the real world.

I have no experience with roller brakes so will not comment on them but as far as 3, 5, and 7 speed internal gear hubs with coaster brakes or no internal brake, Shimano, Sachs/SRAM and S-A; I can affirm that maintenance IS almost zero for years at a time. My current commuter with a Sachs 7 speed coaster brake hubs has served me well for almost 4 years through all weather and road conditions; no problems; approximately 20,000 miles. My three speeds have gone decades with no maintenance.

If the subject is strictly Nexus 8, interested would be wise to post what he actually knows about the specific subject rather than ranting about his aversion to the theoretical "inefficiencies" of "heavy" internal gear hubs for commuting bikes.